This invention relates to toy tractor and semitrailer trucks. In particular, the invention is directed to an improved reciprocating dock for reliably and automatically coupling and uncoupling the semitrailer and the tractor based on reversal of movement of the tractor.
Automatic uncoupling of a toy semitrailer from a toy tractor truck has been proposed in co-pending application Ser. No. 40,860 titled APPARATUS FOR COUPLING AND UNCOUPLING TOY TRUCK TRACTORS AND SEMITRAILERS in the names of D. A. Brand and D. R. Brand wherein a ramp is disposed in a roadway inboard of the tractor wheels. The semitrailer dolly wheels travel up the ramp during the uncoupling operation to pivot the semitrailer upwardly with respect to the tractor. As the semitrailer is pivoted, it releases the tractor.
Automatic coupling of the toy semitrailer to the toy tractor has also been proposed in application Ser. No. 40,860. A simple beveled end is provided on the rear platform of the toy tractor for this purpose. As the tractor backs up to the semitrailer, a king pin on the semitrailer rides up the bevel to the flat area of the rear platform of the tractor and drops into a pivot hole to engage the tractor.
Both the uncoupling and coupling operations are carried out in the same locality and are assisted by a reciprocating dock comprising a bellows. During an uncoupling operation, the dock is contacted and moved backward by the semitrailer as the semitrailer dolly wheels ride up the ramp to release the tractor. As the dock is moved backward, the bellows is compressed. When the direction of movement of the uncoupled tractor is reversed to cause the tractor to depart, the dock and semitrailer are released. The bellows expands to move the dock and semitrailer forwardly so that the semitrailer dolly wheels ride off the ramp and onto the roadway. In this position, the semitrailer is not poised for re-coupling to the tractor. The tractor must subsequently be backed up into the semitrailer and the semitrailer king pin must be moved back up the tractor bevel to re-connect the two vehicles.
Re-connecting the tractor and semitrailer in this fashion may pose a frustrating problem to a child. If the tractor is not stopped quickly after re-connection to the semitrailer, the semitrailer may be moved backwardly such that the dolly wheels travel back up the ramp thereby inadvertently disconnecting the tractor and semitrailer. The child may not possess the eye-hand motor coordination required to stop the tractor quickly after re-connection to the semitrailer to prevent disconnection of the vehicle. Accordingly, a certain degree of unwanted skill is necessary to reliably operate the apparatus described in the aforementioned patent application.